Field of the Disclosure
The present disclosure relates to a cantilever sensor, and more particularly to a cantilever sensor with a slit capable of sensing by way of an electric method through formation of an electrode on a cantilever sensor with a slit, through which a miniaturized cantilever sensor can be realized, and a biosensor having the same.
Discussion of the Related Art
The information disclosed in this Discussion of the Related Art section is only for enhancement of understanding of the general background of the present disclosure and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.
Recently, a miniaturized sensor fabricated by MEMS (Micro Electronic Mechanical System) process has become an object of interest, because the miniaturized sensor fabricated by MEMS process has a quicker response and higher sensitivity and is appropriate to mass production.
Most of the conventional cantilever sensors perform measurement by sensing resonance frequency variation or static deflection due to heat or mass variation using a light source such as laser.
As a measurement of static deflection of a cantilever sensor using an optical system, Nature Biotechnology 18, 856-860 (2001) and Science 288, 316-318 (2000) disclose a detection method of proteins and genes using biological reaction generated from surfaces of a micro cantilever.
The sensing method using static deflection is to determine whether there is a protein or a gene by concentration of laser to a sensing position diode through irradiation of a light source such as the laser to a cantilever surface. However, the method of measuring deformation of cantilever using a light source has a limitation in miniaturization and high integration due to requirement of a predetermined space for installation of optical system.
Furthermore, with regard to researches on micro cantilever sensor using resonance frequency variation, Cornell University reported possibility of detection of particular gas included in vacuum or air by a square cantilever, while Purdue University reported the possibility of detection of particular gas included in vacuum or air by manufacturing a miniaturized cantilever of about 3 μm length. In other examples, U.S. Pat. No. 5,719,324 discloses a cantilever sensor using reaction of chemical materials on a cantilever, particularly using resonance frequency variation for analysis of target chemical material. In other examples, U.S. Pat. Nos. 6,212,939 and 6,289,717 respectively disclose an invention on a chemical sensor by absorption in silicon cantilever, and an invention on a sensing sensor by coupling binding partner of material to be detected from a cantilever. However, the method of measuring the resonance frequency variation has disadvantage in that experimental error is great due to resonance frequency variation in response to viscosity variation of liquid sample, and sensitivity deteriorates due to damping of the cantilever on the liquid sample.
In a measure to overcome the aforementioned disadvantages, MIT attempted to allow the bio reaction to be realized within a cantilever structure by forming a micro-fluidic channel inside the cantilever structure to reduce the damping of the liquid sample, and Tokyo University attempted to increase the sensitivity by making a cantilever structure having a fine slit within several μm ranges as illustrated in FIGS. 1 and 2 (See Lab Chip, 2011 Dec. 21; 11(24):4187-93, Epub 2011 Oct. 28, High-resolution cantilever biosensor resonating at air-liquid in a micro-channel, Park J, Nishida S, Lambert P, Kawakatsu H, Fujita H.). However, the formation of micro-fluidic channel thus discussed has a disadvantage of complicating the cantilever structure, and the cantilever structure having a slit disadvantageously provides a difficulty in miniaturization due to use of laser light source.